Science — CBSE Class 10 board question

(i) The movements that occur all along the gut are called peristaltic movements. The muscular walls of the alimentary canal contract and relax alternately, pushing the food forward. This helps in thorough mixing of food with digestive juices and moves it along the digestive tract for complete digestion and absorption.

(ii) Bile juice is stored in a sac-like organ called the gall bladder.

Two roles of bile juice:

1. It makes the acidic food coming from the stomach alkaline, so that pancreatic enzymes can act on it.
2. It emulsifies fats — breaks large fat globules into smaller droplets, increasing the surface area for enzyme action.

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• "Peristalsis/peristaltic movements" is the exact term examiners expect for (i) — always name it, then explain the mechanism and its role.
• For (ii), both parts are needed: storage location (gall bladder) + two distinct roles. Emulsification of fats and making the medium alkaline are the two standard points from the NCERT Life Processes chapter. Writing "helps in digestion of fats" alone is too vague — specify emulsification.